Apparatus and methods for electrochemical processing of microelectronic workpieces

ABSTRACT

An apparatus and method for electrochemical processing of microelectronic workpieces in a reaction vessel. In one embodiment, the reaction vessel includes: an outer container having an outer wall; a distributor coupled to the outer container, the distributor having a first outlet configured to introduce a primary flow into the outer container and at least one second outlet configured to introduce a secondary flow into the outer container separate from the primary flow; a primary flow guide in the outer container coupled to the distributor to receive the primary flow from the first outlet and direct it to a workpiece processing site; a dielectric field shaping unit in the outer container coupled to the distributor to receive the secondary flow from the second outlet, the field shaping unit being configured to contain the secondary flow separate from the primary flow through at least a portion of the outer container, and the field shaping unit having at least one electrode compartment through which the secondary flow can pass while the secondary flow is separate from the primary flow; an electrode in the electrode compartment; and an interface member carried by the field shaping unit downstream from the electrode, the interface member being in fluid communication with the secondary flow in the electrode compartment, and the interface member being configured to prevent selected matter of the secondary flow from passing to the primary flow.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.09/804,697, entitled “SYSTEM FOR ELECTROCHEMICALLY PROCESSING AWORKPIECE,” filed on Mar. 12, 2001; which is a continuation ofInternational Application No. PCT/US00/10120, filed on Apr. 13, 2000, inthe English language and published in the English language asInternational Publication No. WO00/61498, which claims the benefit ofProvisional Application No. 60/129,055, filed on Apr. 13, 1999, all ofwhich are herein incorporated by reference. Additionally, thisapplication is related to the following:

-   -   (a) U.S. patent application entitled “TRANSFER DEVICES FOR        HANDLING MICROELECTRONIC WORKPIECES WITHIN AN ENVIRONMENT OF A        PROCESSING MACHINE AND METHODS OF MANUFACTURING AND USING SUCH        DEVICES IN THE PROCESSING OF MICROELECTRONIC WORKPIECES,” filed        on Jun. 1, 2001, and identified by Perkins Coie LLP Docket No.        29195.8153US00;    -   (b) U.S. patent application entitled “INTEGRATED TOOLS WITH        TRANSFER DEVICES FOR HANDLING MICROELECTRONIC WORKPIECES,” filed        on Jun. 1, 2001, and identified by Perkins Coie Docket No.        29195.8153US01;    -   (c) U.S. patent application entitled “DISTRIBUTED POWER SUPPLIES        FOR MICROELECTRONIC WORKPIECE PROCESSING TOOLS,” filed on Jun.        1, 2001, and identified by Perkins Coie Docket No.        29195.8155US00;    -   (d) U.S. patent application entitled “ADAPTABLE ELECTROCHEMICAL        PROCESSING CHAMBER,” filed on Jun. 1, 2001, and identified by        Perkins Coie LLP Docket No. 29195.8156US00;    -   (e) U.S. patent application entitled “LIFT AND ROTATE ASSEMBLY        FOR USE IN A WORKPIECE PROCESSING STATION AND A METHOD OF        ATTACHING THE SAME,” filed on Jun. 1, 2001, and identified by        Perkins Coie Docket No. 29195.8154US00;    -   (f) U.S. patent applications entitled “TUNING ELECTRODES USED IN        A REACTOR FOR ELECTROCHEMICALLY PROCESSING A MICROELECTRONIC        WORKPIECE,” one filed on May 4, 2001, and identified by U.S.        application Ser. No. 09/849,505, and two additional applications        filed on May 24, 2001, and identified separately by Perkins Coie        Docket Nos. 29195.8157US02 and 29195.8157US03.

All of the foregoing U.S. patent applications in paragraphs (a)-(f)above are herein incorporated by reference.

TECHNICAL FIELD

This application relates to reaction vessels and methods of making andusing such vessels in electrochemical processing of microelectronicworkpieces.

BACKGROUND

Microelectronic devices, such as semiconductor devices and fieldemission displays, are generally fabricated on and/or in microelectronicworkpieces using several different types of machines (“tools”). Manysuch processing machines have a single processing station that performsone or more procedures on the workpieces. Other processing machines havea plurality of processing stations that perform a series of differentprocedures on individual workpieces or batches of workpieces. In atypical fabrication process, one or more layers of conductive materialsare formed on the workpieces during deposition stages. The workpiecesare then typically subject to etching and/or polishing procedures (i.e.,planarization) to remove a portion of the deposited conductive layersfor forming electrically isolated contacts and/or conductive lines.

Plating tools that plate metals or other materials on the workpieces arebecoming an increasingly useful type of processing machine.Electroplating and electroless plating techniques can be used to depositcopper, solder, permalloy, gold, silver, platinum and other metals ontoworkpieces for forming blanket layers or patterned layers. A typicalcopper plating process involves depositing a copper seed layer onto thesurface of the workpiece using chemical vapor deposition (CVD), physicalvapor deposition (PVD), electroless plating processes, or other suitablemethods. After forming the seed layer, a blanket layer or patternedlayer of copper is plated onto the workpiece by applying an appropriateelectrical potential between the seed layer and an anode in the presenceof an electroprocessing solution. The workpiece is then cleaned, etchedand/or annealed in subsequent procedures before transferring theworkpiece to another processing machine.

FIG. 1 illustrates an embodiment of a single-wafer processing station 1that includes a container 2 for receiving a flow of electroplatingsolution from a fluid inlet 3 at a lower portion of the container 2. Theprocessing station 1 can include an anode 4, a plate-type diffuser 6having a plurality of apertures 7, and a workpiece holder 9 for carryinga workpiece 5. The workpiece holder 9 can include a plurality ofelectrical contacts for providing electrical current to a seed layer onthe surface of the workpiece 5. When the seed layer is biased with anegative potential relative to the anode 4, it acts as a cathode. Inoperation the electroplating fluid flows around the anode 4, through theapertures 7 in the diffuser 6 and against the plating surface of theworkpiece 5. The electroplating solution is an electrolyte that conductselectrical current between the anode 4 and the cathodic seed layer onthe surface of the workpiece 5. Therefore, ions in the electroplatingsolution plate the surface of the workpiece 5.

The plating machines used in fabricating microelectronic devices musteet many specific performance criteria. For example, many processes mustbe able to form small contacts in vias that are less than 0.5 μm wide,and are desirably less than 0.1 μm wide. The plated metal layersaccordingly often need to fill vias or trenches that are on the order of0.1 μm wide, and the layer of plated material should also be depositedto a desired, uniform thickness across the surface of the workpiece 5.One factor that influences the uniformity of the plated layer is themass transfer of electroplating solution at the surface of theworkpiece. This parameter is generally influenced by the velocity of theflow of the electroplating solution perpendicular to the surface of theworkpiece. Another factor that influences the uniformity of the platedlayer is the current density of the electrical field across the surfaceof the wafer.

One concern of existing electroplating equipment is providing a uniformmass transfer at the surface of the workpiece. Referring to FIG. 1,existing plating tools generally use the diffuser 6 to enhance theuniformity of the fluid flow perpendicular to the face of the workpiece.Although the diffuser 6 improves the uniformity of the fluid flow, itproduces a plurality of localized areas of increased flow velocityperpendicular to the surface of the workpiece 5 (indicated by arrows 8).The localized areas generally correspond to the position of theapertures 7 in the diffuser 6. The increased velocity of the fluid flownormal to the substrate in the localized areas increases the masstransfer of the electroplating solution in these areas. This typicallyresults in faster plating rates in the localized areas over theapertures 7. Although many different configurations of apertures havebeen used in plate-type diffusers, these diffusers may not provideadequate uniformity for the precision required in many currentapplications.

Another concern of existing plating tools is that the diffusion layer inthe electroplating solution adjacent to the surface of the workpiece 5can be disrupted by gas bubbles or particles. For example, bubbles canbe introduced to the plating solution by the plumbing and pumping systemof the processing equipment, or they can evolve from inert anodes.Consumable anodes are often used to prevent or reduce the evolvement ofgas bubbles in the electroplating solution, but these anodes erode andthey can form a passivated film surface that must be maintained.Consumable anodes, moreover, often generate particles that can becarried in the plating solution. As a result, gas bubbles and/orparticles can flow to the surface of the workpiece 5, which disrupts theuniformity and affects the quality of the plated layer.

Still another challenge of plating uniform layers is providing a desiredelectrical field at the surface of the workpiece 5. The distribution ofelectrical current in the plating solution is a function of theuniformity of the seed layer across the contact surface, theconfiguration/condition of the anode, and the configuration of thechamber. However, the current density profile on the plating surface canchange. For example, the current density profile typically changesduring a plating cycle because plating material covers the seed layer,or it can change over a longer period of time because the shape ofconsumable anodes changes as they erode and the concentration ofconstituents in the plating solution can change. Therefore, it can bedifficult to maintain a desired current density at the surface of theworkpiece 5.

SUMMARY

The present invention is directed toward reaction vessels forelectrochemical processing of microelectronic workpieces, processingstations including such reaction vessels, and methods for using thesedevices. Several embodiments of reaction vessels in accordance with theinvention solve the problem of providing a desired mass transfer at theworkpiece by configuring the electrodes so that a primary flow guideand/or a field shaping unit in the reaction vessel direct asubstantially uniform primary fluid flow toward the workpiece.Additionally, field shaping units in accordance with several embodimentsof the invention create virtual electrodes such that the workpiece isshielded from the electrodes. This allows for the use of largerelectrodes to increase electrode life, eliminates the need to “burn-in”electrodes to decrease downtime, and/or provides the capability ofmanipulating the electrical field by merely controlling the electricalcurrent to one or more of the electrodes in the vessel. Furthermore,additional embodiments of the invention include interface members in thereaction vessel that inhibit particulates, bubbles and other undesirablematter in the reaction vessel from contacting the workpiece to enhancethe uniformity and the quality of the finished surface on theworkpieces. The interface members can also allow two different types offluids to be used in the reaction vessel, such as a catholyte and ananolyte, to reduce the need to replenish additives as often and to addmore flexibility to designing electrodes and other components in thereaction vessel.

In one embodiment of the invention, a reaction vessel includes an outercontainer having an outer wall, a first outlet configured to introduce aprimary fluid flow into the outer container, and at least one secondoutlet configured to introduce a secondary fluid flow into the outercontainer separate from the primary fluid flow. The reaction vessel canalso include a field shaping unit in the outer container and at leastone electrode. The field shaping unit can be a dielectric assemblycoupled to the second outlet to receive the secondary flow andconfigured to contain the secondary flow separate from the primary flowthrough at least a portion of the outer container. The field shapingunit also has at least one electrode compartment through which thesecondary flow can pass separately from the primary flow. The electrodeis positioned in the electrode compartment.

In a particular embodiment, the field shaping unit has a compartmentassembly having a plurality of electrode compartments and a virtualelectrode unit. The compartment assembly can include a plurality ofannular walls including an inner or first annular wall centered on acommon axis and an outer or second annular wall concentric with thefirst annular wall and spaced radially outward. The annular walls of thefield shaping unit can be positioned inside of outer wall of the outercontainer so that an annular space between the first and second wallsdefines a first electrode compartment and an annular space between thesecond wall and the outer wall defines a second electrode compartment.The reaction vessel of this particular embodiment can have a firstannular electrode in the first electrode compartment and/or a secondannular electrode in the second electrode compartment.

The virtual electrode unit can include a plurality of partitions thathave lateral sections attached to corresponding annular walls of theelectrode compartment and lips that project from the lateral sections.In one embodiment, the first partition has an annular first lip thatdefines a central opening, and the second partition has an annularsecond lip surrounding the first lip that defines an annular opening.

In additional embodiments, the reaction vessel can further include adistributor coupled to the outer container and a primary flow guide inthe outer container. The distributor can include the first outlet andthe second outlet such that the first outlet introduces the primaryfluid flow into the primary flow guide and the second outlet introducesthe secondary fluid flow into the field shaping unit separately from theprimary flow. The primary flow guide can condition the primary flow forproviding a desired fluid flow to a workpiece processing site. In oneparticular embodiment, the primary flow guide directs the primary flowthrough the central opening of the first annular lip of the firstpartition. The secondary flow is distributed to the electrodecompartments of the field shaping unit to establish an electrical fieldin the reaction vessel.

In the operation of one embodiment, the primary flow can pass through afirst flow channel defined, at least in part, by the primary flow guideand the lip of the first partition. The primary flow can be the dominantflow through the reaction vessel so that it controls the mass transferat the workpiece. The secondary flow can generally be contained withinthe field shaping unit so that the electrical field(s) of theelectrode(s) are shaped by the virtual electrode unit and the electrodecompartments. For example, in the embodiment having first and secondannular electrodes, the electrical effect of the first electrode can actas if it is placed in the central opening defined by the lip of thefirst partition, and the electrical effect of the second electrode canact as if it is placed in the annular opening between the first andsecond lips. The actual electrodes, however, can be shielded from theworkpiece by the field shaping unit such that the size and shape of theactual electrodes does not affect the electrical field perceived by theworkpiece.

One feature of several embodiments is that the field shaping unitshields the workpiece from the electrodes. As a result, the electrodescan be much larger than they could without the field shaping unitbecause the size and configuration of the actual electrodes does notappreciably affect the electrical field perceived by the workpiece. Thisis particularly useful when the electrodes are consumable anodes becausethe increased size of the anodes prolongs their life, which reducesdowntime for servicing a tool. Additionally, this reduces the need to“burn-in” anodes because the field shaping element reduces the impactthat films on the anodes have on the shape of the electrical fieldperceived by the workpiece. Both of these benefits significantly improvethe operating efficiency of the reaction vessel.

Another feature of several embodiments of the invention is that theyprovide a uniform mass transfer at the surface of the workpiece. Becausethe field shaping unit separates the actual electrodes from theeffective area where they are perceived by the workpiece, the actualelectrodes can be configured to accommodate internal structure thatguides the flow along a more desirable flow path. For example, thisallows the primary flow to flow along a central path. Moreover, aparticular embodiment includes a central primary flow guide thatprojects the primary flow radially inward along diametrically opposedvectors that create a highly uniform primary flow velocity in adirection perpendicular to the surface of the workpiece.

The reaction vessel can also include an interface member carried by thefield shaping unit downstream from the electrode. The interface membercan be in fluid communication with the secondary flow in the electrodecompartment. The interface member, for example, can be a filter and/oran ion-membrane. In either case, the interface member can inhibitparticulates (e.g., particles from an anode) and bubbles in thesecondary flow from reaching the surface of the workpiece to reducenon-uniformities on the processed surface. This accordingly increasesthe quality of the surface of the workpiece. Additionally, in the caseof an ion-membrane, the interface member can be configured to preventfluids from passing between the secondary flow and the primary flowwhile allowing preferred ions to pass between the flows. This allows theprimary flow and the secondary flow to be different types of fluids,such as a catholyte and an anolyte, which reduces the need to replenishadditives as often and adds more flexibility to designing electrodes andother features of the reaction vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an electroplating chamber in accordancewith the prior art.

FIG. 2 is an isometric view of an electroprocessing machine havingelectroprocessing stations for processing microelectronic workpieces inaccordance with an embodiment of the invention.

FIG. 3 is a cross-sectional view of an electroprocessing station havinga processing chamber for use in an electroprocessing machine inaccordance with an embodiment of the invention. Selected components inFIG. 3 are shown schematically.

FIG. 4 is an isometric view showing a cross-sectional portion of aprocessing chamber taken along line 4-4 of FIG. 8A.

FIGS. 5A-5D are cross-sectional views of a distributor for a processingchamber in accordance with an embodiment of the invention.

FIG. 6 is an isometric view showing a different cross-sectional portionof the processing chamber of FIG. 4 taken along line 6-6 of FIG. 8B.

FIG. 7A is an isometric view of an interface assembly for use in aprocessing chamber in accordance with an embodiment of the invention.

FIG. 7B is a cross-sectional view of the interface assembly of FIG. 7A.

FIGS. 8A and 8B are top plan views of a processing chamber that providea reference for the isometric, cross-sectional views of FIGS. 4 and 6,respectively.

DETAILED DESCRIPTION

The following description discloses the details and features of severalembodiments of electrochemical reaction vessels for use inelectrochemical processing stations and integrated tools to processmicroelectronic workpieces. The term “microelectronic workpiece” is usedthroughout to include a workpiece formed from a substrate upon whichand/or in which microelectronic circuits or components, data storageelements or layers, and/or micro-mechanical elements are fabricated. Itwill be appreciated that several of the details set forth below areprovided to describe the following embodiments in a manner sufficient toenable a person skilled in the art to make and use the disclosedembodiments. Several of the details and advantages described below,however, may not be necessary to practice certain embodiments of theinvention. Additionally, the invention can also include additionalembodiments that are within the scope of the claims, but are notdescribed in detail with respect to FIGS. 2-8B.

The operation and features of electrochemical reaction vessels are bestunderstood in light of the environment and equipment in which they canbe used to electrochemically process workpieces (e.g., electroplateand/or electropolish). As such, embodiments of integrated tools withprocessing stations having the electrochemical reaction vessels areinitially described with reference to FIGS. 2 and 3. The details andfeatures of several embodiments of electrochemical reaction vessels arethen described with reference to FIGS. 4-8B.

A. Selected Embodiments of Integrated Tools with ElectrochemicalProcessing Stations

FIG. 2 is an isometric view of a processing machine 100 having anelectrochemical processing station 120 in accordance with an embodimentof the invention. A portion of the processing machine 100 is shown in acut-away view to illustrate selected internal components. In one aspectof this embodiment, the processing machine 100 can include a cabinet 102having an interior region 104 defining an interior enclosure that is atleast partially isolated from an exterior region 105. The cabinet 102can also include a plurality of apertures 106 (only one shown in FIG. 1)through which microelectronic workpieces 101 can ingress and egressbetween the interior region 104 and a load/unload station 110.

The load/unload station 110 can have two container supports 112 that areeach housed in a protective shroud 113. The container supports 112 areconfigured to position workpiece containers 114 relative to theapertures 106 in the cabinet 102. The workpiece containers 114 can eachhouse a plurality of microelectronic workpieces 101 in a “mini” cleanenvironment for carrying a plurality of workpieces through otherenvironments that are not at clean room standards. Each of the workpiececontainers 114 is accessible from the interior region 104 of the cabinet102 through the apertures 106.

The processing machine 100 can also include a plurality ofelectrochemical processing stations 120 and a transfer device 130 in theinterior region 104 of the cabinet 102. The processing machine 100, forexample, can be a plating tool that also includes clean/etch capsules122, electroless plating stations, annealing stations, and/or metrologystations.

The transfer device 130 includes a linear track 132 extending in alengthwise direction of the interior region 104 between the processingstations. The transfer device 130 can further include a robot unit 134carried by the track 132. In the particular embodiment shown in FIG. 2,a first set of processing stations is arranged along a first row R₁-R₁and a second set of processing stations is arranged long a second rowR₂-R₂. The linear track 132 extends between the first and second rows ofprocessing stations, and the robot unit 134 can access any of theprocessing stations along the track 132.

FIG. 3 illustrates an embodiment of an electrochemical-processingchamber 120 having a head assembly 150 and a processing chamber 200. Thehead assembly 150 includes a spin motor 152, a rotor 154 coupled to thespin motor 152, and a contact assembly 160 carried by the rotor 154. Therotor 154 can have a backing plate 155 and a seal 156. The backing plate155 can move transverse to a workpiece 101 (arrow T) between a firstposition in which the backing plate 155 contacts a backside of theworkpiece 101 (shown in solid lines in FIG. 3) and a second position inwhich it is spaced apart from the backside of the workpiece 101 (shownin broken lines in FIG. 3). The contact assembly 160 can have a supportmember 162, a plurality of contacts 164 carried by the support member162, and a plurality of shafts 166 extending between the support member162 and the rotor 154. The contacts 164 can be ring-type spring contactsor other types of contacts that are configured to engage a portion ofthe seed-layer on the workpiece 101. Commercially available headassemblies 150 and contact assemblies 160 can be used in theelectroprocessing chamber 120. Particular suitable head assemblies 150and contact assemblies 160 are disclosed in U.S. Pat. Nos. 6,228,232 and6,080,691; and U.S. application Ser. Nos. 09/385,784; 09/386,803;09/386,610; 09/386,197; 09/501,002; 09/733,608; and 09/804,696, all ofwhich are herein incorporated by reference.

The processing chamber 200 includes an outer housing 202 (shownschematically in FIG. 3) and a reaction vessel 204 (also shownschematically in FIG. 3) in the housing 202. The reaction vessel 204carries at least one electrode (not shown in FIG. 3) and directs a flowof electroprocessing solution to the workpiece 101. Theelectroprocessing solution, for example, can flow over a weir (arrow F)and into the external housing 202, which captures the electroprocessingsolution and sends it back to a tank. Several embodiments of reactionvessels 204 are shown and described in detail with reference to FIGS.4-8B.

In operation the head assembly 150 holds the workpiece at aworkpiece-processing site of the reaction vessel 204 so that at least aplating surface of the workpiece engages the electroprocessing solution.An electrical field is established in the solution by applying anelectrical potential between the plating surface of the workpiece viathe contact assembly 160 and one or more electrodes in the reactionvessel 204. For example, the contact assembly 160 can be biased with anegative potential with respect to the electrode(s) in the reactionvessel 204 to plate materials onto the workpiece. On the other hand thecontact assembly 160 can be biased with a positive potential withrespect to the electrode(s) in the reaction vessel 204 to (a) de-plateor electropolish plated material from the workpiece or (b) deposit othermaterials (e.g., electrophoric resist). In general, therefore, materialscan be deposited on or removed from the workpiece with the workpieceacting as a cathode or an anode depending upon the particular type ofmaterial used in the electrochemical process.

B. Selected Embodiments of Reaction Vessels for Use in ElectrochemicalProcessing Chambers

FIGS. 4-8B illustrate several embodiments of reaction vessels 204 foruse in the processing chamber 200. As explained above, the housing 202carries the reaction vessel 204. The housing 202 can have a drain 210for returning the processing fluid that flows out of the reaction vessel204 to a storage tank, and a plurality of openings for receiving inletsand electrical fittings. The reaction vessel 204 can include an outercontainer 220 having an outer wall 222 spaced radially inwardly of thehousing 202. The outer container 220 can also have a spiral spacer 224between the outer wall 222 and the housing 202 to provide a spiral ramp(i.e., a helix) on which the processing fluid can flow downward to thebottom of the housing 202. The spiral ramp reduces the turbulence of thereturn fluid to inhibit entrainment of gasses in the return fluid.

The particular embodiment of the reaction vessel 204 shown in FIG. 4 caninclude a distributor 300 for receiving a primary fluid flow F_(p) and asecondary fluid flow F₂, a primary flow guide 400 coupled to thedistributor 300 to condition the primary fluid flow F_(p), and a fieldshaping unit 500 coupled to the distributor 300 to contain the secondaryflow F₂ in a manner that shapes the electrical field in the reactionvessel 204. The reaction vessel 204 can also include at least oneelectrode 600 in a compartment of the field shaping unit 500 and atleast one filter or other type of interface member 700 carried by thefield shaping unit 500 downstream from the electrode. The primary flowguide 400 can condition the primary flow F_(p) by projecting this flowradially inwardly relative to a common axis A-A, and a portion of thefield shaping unit 500 directs the conditioned primary flow F_(p) towardthe workpiece. In several embodiments, the primary flow passing throughthe primary flow guide 400 and the center of the field shaping unit 500controls the mass transfer of processing solution at the surface of theworkpiece. The field shaping unit 500 also defines the shape theelectric field, and it can influence the mass transfer at the surface ofthe workpiece if the secondary flow passes through the field shapingunit. The reaction vessel 204 can also have other configurations ofcomponents to guide the primary flow F_(p) and the secondary flow F₂through the processing chamber 200. The reaction vessel 204, forexample, may not have a distributor in the processing chamber, butrather separate fluid lines with individual flows can be coupled to thevessel 204 to provide a desired distribution of fluid through theprimary flow guide 400 and the field shaping unit. For example, thereaction vessel 204 can have a first outlet in the outer container 220for introducing the primary flow into the reaction vessel and a secondoutlet in the outer container for introducing the secondary flow intothe reaction vessel 204. Each of these components is explained in moredetail below.

FIGS. 5A-5D illustrate an embodiment of the distributor 300 fordirecting the primary fluid flow to the primary flow guide 400 and thesecondary fluid flow to the field shaping unit 500. Referring to FIG.5A, the distributor 300 can include a body 310 having a plurality ofannular steps 312 (identified individually by reference numbers 312 a-d)and annular grooves 314 in the steps 312. The outermost step 312 d isradially inward of the outer wall 222 (shown in broken lines) of theouter container 220 (FIG. 4), and each of the interior steps 312 a-c cancarry an annular wall (shown in broken lines) of the field shaping unit500 in a corresponding groove 314. The distributor 300 can also includea first inlet 320 for receiving the primary flow F_(p) and a plenum 330for receiving the secondary flow F₂. The first inlet 320 can have aninclined, annular cavity 322 to form a passageway 324 (best shown inFIG. 4) for directing the primary fluid flow F_(p) under the primaryflow guide 400. The distributor 300 can also have a plurality of upperorifices 332 along an upper part of the plenum 330 and a plurality oflower orifices 334 along a lower part of the plenum 330. As explained inmore detail below, the upper and lower orifices are open to channelsthrough the body 310 to distribute the secondary flow F₂ to the risersof the steps 312. The distributor 300 can also have otherconfigurations, such as a “step-less” disk or non-circular shapes.

FIGS. 5A-5D further illustrate one configuration of channels through thebody 310 of the distributor 300. Referring to FIG. 5A, a number of firstchannels 340 extend from some of the lower orifices 334 to openings atthe riser of the first step 312 a. FIG. 5B shows a number of secondchannels 342 extending from the upper orifices 332 to openings at theriser of the second step 312 b, and FIG. 5C shows a number of thirdchannels 344 extending from the upper orifices 332 to openings at theriser of the third step 312 c. Similarly, FIG. 5D illustrates a numberof fourth channels 346 extending from the lower orifices 334 to theriser of the fourth step 312 d.

The particular embodiment of the channels 340-346 in FIGS. 5A-5D areconfigured to transport bubbles that collect in the plenum 330 radiallyoutward as far as practical so that these bubbles can be captured andremoved from the secondary flow F₂. This is beneficial because the fieldshaping unit 500 removes bubbles from the secondary flow F₂ bysequentially transporting the bubbles radially outwardly throughelectrode compartments. For example, a bubble B in the compartment abovethe first step 312 a can sequentially cascade through the compartmentsover the second and third steps 312 b-c, and then be removed from thecompartment above the fourth step 312 d. The first channel 340 (FIG. 5A)accordingly carries fluid from the lower orifices 334 where bubbles areless likely to collect to reduce the amount of gas that needs to cascadefrom the inner compartment above the first step 312 a all the way out tothe outer compartment. The bubbles in the secondary flow F₂ are morelikely to collect at the top of the plenum 330 before passing throughthe channels 340-346. The upper orifices 332 are accordingly coupled tothe second channel 342 and the third channel 344 to deliver thesebubbles outward beyond the first step 312 a so that they do not need tocascade through so many compartments. In this embodiment, the upperorifices 332 are not connected to the fourth channels 346 because thiswould create a channel that inclines downwardly from the common axissuch that it may conflict with the groove 314 in the third step 312 c.Thus, the fourth channel 346 extends from the lower orifices 334 to thefourth step 312 d.

Referring again to FIG. 4, the primary flow guide 400 receives theprimary fluid flow F_(p) via the first inlet 320 of the distributor 300.In one embodiment, the primary flow guide 400 includes an inner baffle410 and an outer baffle 420. The inner baffle can have a base 412 and awall 414 projecting upward and radially outward from the base 412. Thewall 414, for example, can have an inverted frusto-conical shape and aplurality of apertures 416. The apertures 416 can be holes, elongatedslots or other types of openings. In the illustrated embodiment, theapertures 416 are annularly extending radial slots that slant upwardrelative to the common axis to project the primary flow radially inwardand upward relative to the common axis along a plurality ofdiametrically opposed vectors. The inner baffle 410 can also includes alocking member 418 that couples the inner baffle 410 to the distributor300.

The outer baffle 420 can include an outer wall 422 with a plurality ofapertures 424. In this embodiment, the apertures 424 are elongated slotsextending in a direction transverse to the apertures 416 of the innerbaffle 410. The primary flow F_(p) flows through (a) the first inlet320, (b) the passageway 324 under the base 412 of the inner baffle 410,(c) the apertures 424 of the outer baffle 420, and then (d) theapertures 416 of the inner baffle 410. The combination of the outerbaffle 420 and the inner baffle 410 conditions the direction of the flowat the exit of the apertures 416 in the inner baffle 410. The primaryflow guide 400 can thus project the primary flow along diametricallyopposed vectors that are inclined upward relative to the common axis tocreate a fluid flow that has a highly uniform velocity. In alternateembodiments, the apertures 416 do not slant upward relative to thecommon axis such that they can project the primary flow normal, or evendownward, relative to the common axis.

FIG. 4 also illustrates an embodiment of the field shaping unit 500 thatreceives the primary fluid flow F_(p) downstream from the primary flowguide 400. The field shaping unit 500 also contains the second fluidflow F₂ and shapes the electrical field within the reaction vessel 204.In this embodiment, the field shaping unit 500 has a compartmentstructure with a plurality of walls 510 (identified individually byreference numbers 510 a-d) that define electrode compartments 520(identified individually by reference numbers 520 a-d). The walls 510can be annular skirts or dividers, and they can be received in one ofthe annular grooves 314 in the distributor 300. In one embodiment, thewalls 510 are not fixed to the distributor 300 so that the field shapingunit 500 can be quickly removed from the distributor 300. This allowseasy access to the electrode compartments 520 and/or quick removal ofthe field shaping unit 500 to change the shape of the electric field.

The field shaping unit 500 can have at least one wall 510 outward fromthe primary flow guide 400 to prevent the primary flow F_(p) fromcontacting an electrode. In the particular embodiment shown in FIG. 4,the field shaping unit 500 has a first electrode compartment 520 adefined by a first wall 510 a and a second wall 510 b, a secondelectrode compartment 520 b defined by the second wall 510 b and a thirdwall 510 c, a third electrode compartment 520 c defined by the thirdwall δ 10 c and a fourth wall 510 d, and a fourth electrode compartment520 d defined by the fourth wall 510 d and the outer wall 222 of thecontainer 220. The walls 510 a-d of this embodiment are concentricannular dividers that define annular electrode compartments 520 a-d.Alternate embodiments of the field shaping unit can have walls withdifferent configurations to create non-annular electrode compartmentsand/or each electrode compartment can be further divided into cells. Thesecond-fourth walls 510 b-d can also include holes 522 for allowingbubbles in the first-third electrode compartments 520 a-c to “cascade”radially outward to the next outward electrode compartment 520 asexplained above with respect to FIGS. 5A-5D. The bubbles can then exitthe fourth electrode compartment 520 d through an exit hole 525 throughthe outer wall 222. In an alternate embodiment, the bubbles can exitthrough an exit hole 524.

The electrode compartments 520 provide electrically discretecompartments to house an electrode assembly having at least oneelectrode and generally two or more electrodes 600 (identifiedindividually by reference numbers 600 a-d). The electrodes 600 can beannular members (e.g., annular rings or arcuate sections) that areconfigured to fit within annular electrode compartments, or they canhave other shapes appropriate for the particular workpiece (e.g.,rectilinear). In the illustrated embodiment, for example, the electrodeassembly includes a first annular electrode 600 a in the first electrodecompartment 520 a, a second annular electrode 600 b in the secondelectrode compartment 520 b, a third annular electrode 600 c in thethird electrode compartment 520 c, and a fourth annular electrode 600 din the fourth electrode compartment 520 d. As explained in U.S.Application Nos. 60/206,661, 09/845,505, and 09/804,697, all of whichare incorporated herein by reference, each of the electrodes 600 a-d canbe biased with the same or different potentials with respect to theworkpiece to control the current density across the surface of theworkpiece. In alternate embodiments, the electrodes 600 can benon-circular shapes or sections of other shapes.

Embodiments of the reaction vessel 204 that include a plurality ofelectrodes provide several benefits for plating or electropolishing. Inplating applications, for example, the electrodes 600 can be biased withrespect to the workpiece at different potentials to provide uniformplating on different workpieces even though the seed layers vary fromone another or the bath(s) of electroprocessing solution have differentconductivities and/or concentrations of constituents. Additionally,another the benefit of having a multiple electrode design is thatplating can be controlled to achieve different final fill thicknesses ofplated layers or different plating rates during a plating cycle or indifferent plating cycles. Other benefits of particular embodiments arethat the current density can be controlled to (a) provide a uniformcurrent density during feature filling and/or (b) achieve plating tospecific film profiles across a workpiece (e.g., concave, convex, flat).Accordingly, the multiple electrode configurations in which theelectrodes are separate from one another provide several benefits forcontrolling the electrochemical process to (a) compensate fordeficiencies or differences in seed layers between workpieces, (b)adjust for variances in baths of electroprocessing solutions, and/or (c)achieve predetermined feature filling or film profiles.

The field shaping unit 500 can also include a virtual electrode unitcoupled to the walls 510 of the compartment assembly for individuallyshaping the electrical fields produced by the electrodes 600. In theparticular embodiment illustrated in FIG. 4, the virtual electrode unitincludes first-fourth partitions 530 a-530 d, respectively. The firstpartition 530 a can have a first section 532 a coupled to the secondwall 510 b, a skirt 534 depending downward above the first wall 510 a,and a lip 536 a projecting upwardly. The lip 536 a has an interiorsurface 537 that directs the primary flow F_(p) exiting from the primaryflow guide 400. The second partition 530 b can have a first section 532b coupled to the third wall 510 c and a lip 536 b projecting upward fromthe first section 532 b, the third partition 530 c can have a firstsection 532 c coupled to the fourth wall 510 d and a lip 536 cprojecting upward from the first section 532 c, and the fourth partition530 d can have a first section 532 d carried by the outer wall 222 ofthe container 220 and a lip 536 d projecting upward from the firstsection 532 d. The fourth partition 530 d may not be connected to theouter wall 222 so that the field shaping unit 500 can be quickly removedfrom the vessel 204 by simply lifting the virtual electrode unit. Theinterface between the fourth partition 530 d and the outer wall 222 issealed by a seal 527 to inhibit both the fluid and the electricalcurrent from leaking out of the fourth electrode compartment 520 d. Theseal 527 can be a lip seal. Additionally, each of the sections 532 a-dcan be lateral sections extending transverse to the common axis.

The individual partitions 530 a-d can be machined from or molded into asingle piece of dielectric material, or they can be individualdielectric members that are welded together. In alternate embodiments,the individual partitions 530 a-d are not attached to each other and/orthey can have different configurations. In the particular embodimentshown in FIG. 4, the partitions 530 a-d are annular horizontal members,and each of the lips 536 a-d are annular vertical members arrangedconcentrically about the common axis.

The walls 510 and the partitions 530 a-d are generally dielectricmaterials that contain the second flow F₂ of the processing solution forshaping the electric fields generated by the electrodes 600 a-d. Thesecond flow F₂, for example, can pass (a) through each of the electrodecompartments 520 a-d, (b) between the individual partitions 530 a-d, andthen (c) upward through the annular openings between the lips 536 a-d.In this embodiment, the secondary flow F₂ through the first electrodecompartment 520 a can join the primary flow F_(p) in an antechamber justbefore the primary flow guide 400, and the secondary flow through thesecond-fourth electrode compartments 520 b-d can join the primary flowF_(p) beyond the top edges of the lips 536 a-d. The flow ofelectroprocessing solution then flows over a shield weir attached at rim538 and into the gap between the housing 202 and the outer wall 222 ofthe container 220 as disclosed in International Application No.PCT/US00/10120. The fluid in the secondary flow F₂ can be prevented fromflowing out of the electrode compartments 520 a-d to join the primaryflow F_(p) while still allowing electrical current to pass from theelectrodes 600 to the primary flow. In this alternate embodiment, thesecondary flow F₂ can exit the reaction vessel 204 through the holes 522in the walls 510 and the hole 525 in the outer wall 222. In stilladditional embodiments in which the fluid of the secondary flow does notjoin the primary flow, a duct can be coupled to the exit hole 525 in theouter wall 222 so that a return flow of the secondary flow passing outof the field shaping unit 500 does not mix with the return flow of theprimary flow passing down the spiral ramp outside of the outer wall 222.The field shaping unit 500 can have other configurations that aredifferent than the embodiment shown in FIG. 4. For example, theelectrode compartment assembly can have only a single wall 510 defininga single electrode compartment 520, and the reaction vessel 204 caninclude only a single electrode 600. The field shaping unit of eitherembodiment still separates the primary and secondary flows so that theprimary flow does not engage the electrode, and thus it shields theworkpiece from the single electrode. One advantage of shielding theworkpiece from the electrodes 600 a-d is that the electrodes canaccordingly be much larger than they could be without the field shapingunit because the size of the electrodes does not have an effect on theelectrical field presented to the workpiece. This is particularly usefulin situations that use consumable electrodes because increasing the sizeof the electrodes prolongs the life of each electrode, which reducesdowntime for servicing and replacing electrodes.

An embodiment of reaction vessel 204 shown in FIG. 4 can accordinglyhave a first conduit system for conditioning and directing the primaryfluid flow F_(p) to the workpiece, and a second conduit system forconditioning and directing the secondary fluid flow F₂. The firstconduit system, for example, can include the inlet 320 of thedistributor 300; the channel 324 between the base 412 of the primaryflow guide 400 and the inclined cavity 322 of the distributor 300; aplenum between the wall 422 of the outer baffle 420 and the first wall510 a of the field shaping unit 500; the primary flow guide 400; and theinterior surface 537 of the first lip 536 a. The first conduit systemconditions the direction of the primary fluid flow F_(p) by passing itthrough the primary flow guide 400 and along the interior surface 537 sothat the velocity of the primary flow F_(p) normal to the workpiece isat least substantially uniform across the surface of the workpiece. Theprimary flow Fp and the rotation of the workpiece can accordingly becontrolled to dominate the mass transfer of electroprocessing medium atthe workpiece.

The second conduit system, for example, can include the plenum 330 andthe channels 340-346 of the distributor 300, the walls 510 of the fieldshaping unit 500, and the partitions 530 of the field shaping unit 500.The secondary flow F₂ contacts the electrodes 600 to establishindividual electrical fields in the field shaping unit 500 that areelectrically coupled to the primary flow F_(p). The field shaping unit500, for example, separates the individual electrical fields created bythe electrodes 600 a-d to create “virtual electrodes” at the top of theopenings defined by the lips 536 a-d of the partitions. In thisparticular embodiment, the central opening inside the first lip 536 adefines a first virtual electrode, the annular opening between the firstand second lips 536 a-b defines a second virtual electrode, the annularopening between the second and third lips 536 b-c defines a thirdvirtual electrode, and the annular opening between the third and fourthlips 536 c-d defines a fourth virtual electrode. These are “virtualelectrodes” because the field shaping unit 500 shapes the individualelectrical fields of the actual electrodes 600 a-d so that the effect ofthe electrodes 600 a-d acts as if they are placed between the top edgesof the lips 536 a-d. This allows the actual electrodes 600 a-d to beisolated from the primary fluid flow, which can provide several benefitsas explained in more detail below.

An additional embodiment of the processing chamber 200 includes at leastone interface member 700 (identified individually by reference numbers700 a-d) for further conditioning the secondary flow F₂ ofelectroprocessing solution. The interface members 700, for example, canbe filters that capture particles in the secondary flow that weregenerated by the electrodes (i.e., anodes) or other sources ofparticles. The filter-type interface members 700 can also inhibitbubbles in the secondary flow F₂ from passing into the primary flowF_(p) of electroprocessing solution. This effectively forces the bubblesto pass radially outwardly through the holes 522 in the walls 510 of thefield shaping unit 500. In alternate embodiments, the interface members700 can be ion-membranes that allow ions in the secondary flow F₂ topass through the interface members 700. The ion-membrane interfacemembers 700 can be selected to (a) allow the fluid of theelectroprocessing solution and ions to pass through the interface member700, or (b) allow only the desired ions to pass through the interfacemember such that the fluid itself is prevented from passing beyond theion-membrane.

FIG. 6 is another isometric view of the reaction vessel 204 of FIG. 4showing a cross-sectional portion taken along a different cross-section.More specifically, the cross-section of FIG. 4 is shown in FIG. 8A andthe cross-section of FIG. 6 is shown in FIG. 8B. Returning now to FIG.6, this illustration further shows one embodiment for configuring aplurality of interface members 700 a-d relative to the partitions 530a-d of the field shaping unit 500. A first interface member 700 a can beattached to the skirt 534 of the first partition 530 a so that a firstportion of the secondary flow F₂ flows past the first electrode 600 a,through an opening 535 in the skirt 534, and then to the first interfacemember 700 a. Another portion of the secondary flow F₂ can flow past thesecond electrode 600 b to the second interface member 700 b. Similarly,portions of the secondary flow F₂ can flow past the third and fourthelectrodes 600 c-d to the third and fourth interface members 700 c-d.

When the interface members 700 a-d are filters or ion-membranes thatallow the fluid in the secondary flow F₂ to pass through the interfacemembers 700 a-d, the secondary flow F₂ joins the primary fluid flowF_(p). The portion of the secondary flow F₂ in the first electrodecompartment 520 a can pass through the opening 535 in the skirt 534 andthe first interface member 700 a, and then into a plenum between thefirst wall 510 a and the outer wall 422 of the baffle 420. This portionof the secondary flow F₂ accordingly joins the primary flow F_(p) andpasses through the primary flow guide 400. The other portions of thesecondary flow F₂ in this particular embodiment pass through thesecond-fourth electrode compartments 520 b-d and then through theannular openings between the lips 536 a-d. The second-fourth interfacemembers 700 b-d can accordingly be attached to the field shaping unit500 downstream from the second-fourth electrodes 600 b-d.

In the particular embodiment shown in FIG. 6, the second interfacemember 700 b is positioned vertically between the first and secondpartitions 530 a-b, the third interface member 700 c is positionedvertically between the second and third partitions 530 b-c, and thefourth interface member 700 d is positioned vertically between the thirdand fourth partitions 530 c-d. The interface assemblies 710 a-d aregenerally installed vertically, or at least at an upwardly inclinedangle relative to horizontal, to force the bubbles to rise so that theycan escape through the holes 522 in the walls 510 a-d (FIG. 4). Thisprevents aggregations of bubbles that could potentially disrupt theelectrical field from an individual electrode.

FIGS. 7A and 7B illustrate an interface assembly 710 for mounting theinterface members 700 to the field shaping unit 500 in accordance withan embodiment of the invention. The interface assembly 710 can includean annular interface member 700 and a fixture 720 for holding theinterface member 700. The fixture 720 can include a first frame 730having a plurality of openings 732 and a second frame 740 having aplurality of openings 742 (best shown in FIG. 7A). The holes 732 in thefirst frame can be aligned with the holes 742 in the second frame 740.The second frame can further include a plurality of annular teeth 744extending around the perimeter of the second frame. It will beappreciated that the teeth 744 can alternatively extend in a differentdirection on the exterior surface of the second frame 740 in otherembodiments, but the teeth 744 generally extend around the perimeter ofthe second frame 740 in a top annular band and a lower annular band toprovide annular seals with the partitions 536 a-d (FIG. 6). Theinterface member 700 can be pressed between the first frame 730 and thesecond frame 740 to securely hold the interface member 700 in place. Theinterface assembly 710 can also include a top band 750 a extendingaround the top of the frames 730 and 740 and a bottom band 750 bextending around the bottom of the frames 730 and 740. The top andbottom bands 750 a-b can be welded to the frames 730 and 740 by annularwelds 752. Additionally, the first and second frames 730 and 740 can bewelded to each other by welds 754. It will be appreciated that theinterface assembly 710 can have several different embodiments that aredefined by the configuration of the field shaping unit 500 (FIG. 6) andthe particular configuration of the electrode compartments 520 a-d (FIG.6).

When the interface member 700 is a filter material that allows thesecondary flow F₂ of electroprocessing solution to pass through theholes 732 in the first frame 730, the post-filtered portion of thesolution continues along a path (arrow Q) to join the primary fluid flowF_(p) as described above. One suitable material for a filter-typeinterface member 700 is POREX®, which is a porous plastic that filtersparticles to prevent them from passing through the interface member. Inplating systems that use consumable anodes (e.g., phosphorized copper ornickel sulfamate), the interface member 700 can prevent the particlesgenerated by the anodes from reaching the plating surface of theworkpiece.

In alternate embodiments in which the interface member 700 is anion-membrane, the interface member 700 can be permeable to preferredions to allow these ions to pass through the interface member 700 andinto the primary fluid flow F_(p). One suitable ion-membrane is NAFION®perfluorinated membranes manufactured by DuPont®. In one application forcopper plating, a NAFION 450 on-selective membrane is used. Othersuitable types of ion-membranes for plating can be polymers that arepermeable to many cations, but reject anions and non-polar species. Itwill be appreciated that in electropolishing applications, the interfacemember 700 may be selected to be permeable to anions, but reject cationsand non-polar species. The preferred ions can be transferred through theion-membrane interface member 700 by a driving force, such as adifference in concentration of ions on either side of the membrane, adifference in electrical potential, or hydrostatic pressure.

Using an ion-membrane that prevents the fluid of the electroprocessingsolution from passing through the interface member 700 allows theelectrical current to pass through the interface member while filteringout particles, organic additives and bubbles in the fluid. For example,in plating applications in which the interface member 700 is permeableto cations, the primary fluid flow F_(p) that contacts the workpiece canbe a catholyte and the secondary fluid flow F₂ that does not contact theworkpiece can be a separate anolyte because these fluids do not mix inthis embodiment. A benefit of having separate anolyte and catholytefluid flows is that it eliminates the consumption of additives at theanodes and thus the need to replenish the additives as often.Additionally, this feature combined with the “virtual electrode” aspectof the reaction vessel 204 reduces the need to “burn-in” anodes forinsuring a consistent black film over the anodes for predictable currentdistribution because the current distribution is controlled by theconfiguration of the field shaping unit 500. Another advantage is thatit also eliminates the need to have a predictable consumption ofadditives in the secondary flow F₂ because the additives to thesecondary flow F₂ do not effect the primary fluid flow F_(p) when thetwo fluids are separated from each other.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1-90. (canceled)
 91. A method of electrochemically processingmicroelectronic workpieces in a reaction vessel having a workpieceprocessing zone, the method comprising: passing a processing fluidthrough a distributor in the reaction vessel by flowing the processingfluid through a first channel of the distributor and a second channel ofthe distributor; receiving the processing fluid from the first channelin a first electrode compartment in the reaction vessel in which a firstelectrode is positioned and flowing the processing fluid through thefirst electrode compartment; receiving the processing fluid from thesecond channel in a second electrode compartment in the reaction vesselin which a second electrode is positioned and flowing the processingfluid through the second electrode compartment; applying a firstelectrical potential to the first electrode and applying a secondelectrical potential to the second electrode that is different than thefirst electrical potential; and inhibiting matter in the processingfluid from passing out of the first and second electrode compartmentsand to the processing zone.
 92. The method of claim 91, furthercomprising changing at least one of the first electrical potentialand/or the second electrical potential while processing a workpiece. 93.The method of claim 91, further comprising directing a primary fluidflow through the reaction vessel toward the processing zone, and whereinthe processing fluid flowing through the first and second channels ofthe distributor comprises a secondary flow of processing fluid that isseparated from the primary fluid flow through at least a portion of thereaction vessel.
 94. The method of claim 93 wherein the primary fluidflow comprises a catholyte and the secondary fluid flow comprises ananolyte.
 95. The method of claim 94, further comprising contacting asurface of a microelectronic workpiece with the catholyte.
 96. Themethod of claim 95, further comprising changing at least one of thefirst electrical potential and/or the second electrical potential whilecontacting the surface of the microelectronic workpiece with thecatholyte.
 97. The method of claim 91, further comprising: directing aprimary fluid flow of a catholyte through the reaction vessel toward theprocessing zone; contacting a surface of a microelectronic workpiecewith the catholyte; and separating the primary fluid flow of thecatholyte from the processing fluid flowing through the first and secondelectrode compartments, wherein the processing fluid flowing through thefirst and second electrode compartment comprises an anolyte and definesa secondary fluid flow.
 98. The method of claim 97 wherein separatingthe primary fluid flow from the secondary fluid flow comprises providingan ion-membrane in the reaction vessel located between the processingzone and at least one of the first and second electrode compartments.99. A method of electrochemically processing a microelectronic workpiecein a reaction vessel having a workpiece processing zone, the methodcomprising: directing an electrolytic processing fluid through a portionof the reaction vessel by passing the processing fluid through an inletin the reaction vessel, flowing a first portion of the processing fluidfrom the inlet and through a first channel in the reaction vessel to afirst electrode compartment in the reaction vessel, and flowing a secondportion of the processing fluid from the inlet and through a secondchannel in the reaction vessel to a second electrode compartment in thereaction vessel; inhibiting matter in the processing fluid from passingout of the electrode compartments and flowing to the processing zone;applying a first electrical potential to a first electrode in the firstelectrode compartment and applying a second electrical potential to asecond electrode in the second electrode compartment, wherein the firstelectrical potential is different than the second electrical potential;and subjecting a surface of a microelectronic workpiece to an electricalfield established by the first and second electrodes.
 100. The method ofclaim 99, further comprising changing at least one of the firstelectrical potential and/or the second electrical potential whilesubjecting the workpiece to the electrical field.
 101. The method ofclaim 99, further comprising directing a primary fluid flow through thereaction vessel toward the processing zone, and wherein the processingfluid flowing through the first and second channels of the distributorcomprises a secondary flow of processing fluid that is separated fromthe primary fluid flow through at least a portion of the reactionvessel.
 102. The method of claim 101 wherein the primary fluid flowcomprises a catholyte and the secondary fluid flow comprises an anolyte.103. The method of claim 102 wherein subjecting the surface of themicroelectronic workpiece to the electrical field established by thefirst and second electrodes comprises contacting the surface of amicroelectronic workpiece with the catholyte.
 104. The method of claim103, further comprising changing at least one of the first electricalpotential and/or the second electrical potential while contacting thesurface of the microelectronic workpiece with the catholyte.
 105. Themethod of claim 99, further comprising: directing a primary fluid flowof a catholyte through the reaction vessel toward the processing zone;and separating the primary fluid flow of the catholyte from theprocessing fluid flowing through the first and second electrodecompartments, wherein the processing fluid flowing through the first andsecond electrode compartment comprises an anolyte and defines asecondary fluid flow.
 106. The method of claim 105 wherein separatingthe primary fluid flow from the secondary fluid flow comprises providingan ion-membrane in the reaction vessel located between the processingzone and at least one of the first and second electrode compartments.107. A method of electrochemically processing a microelectronicworkpiece in a reaction vessel having a workpiece processing zone, themethod comprising: directing a primary fluid flow through the reactionvessel and to the processing zone; contacting a surface of amicroelectronic workpiece with the primary fluid flow; directing asecondary fluid flow through at least a portion of the reaction vesselsuch that a first portion of the secondary fluid flow passes through afirst electrode compartment in the reaction vessel in which a firstelectrode is positioned and a second portion of the secondary fluid flowpasses through a second electrode compartment in the reaction vessel inwhich a second electrode is positioned; and inhibiting matter in thesecondary fluid flow from passing into the primary fluid flow.
 108. Themethod of claim 107, further comprising: applying a first electricalpotential to the first electrode and applying a second electricalpotential to the second electrode; and changing at least one of thefirst electrical potential and/or the second electrical potential whileprocessing a workpiece.
 109. The method of claim 107 wherein thesecondary fluid flow is separated from the primary fluid flow through atleast a portion of the reaction vessel.
 110. The method of claim 109wherein the primary fluid flow comprises a catholyte and the secondaryfluid flow comprises an anolyte.
 111. The method of claim 107, furthercomprising separating the primary fluid flow from the secondary fluidflow by providing an ion-membrane in the reaction vessel located betweenthe processing zone and at least one of the first and second electrodecompartments.